


Your Hand in Mine

by tealmoon



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Alternate Universe - Underswap, Cherryberry - Freeform, Fisting, M/M, No Genitals, Semi-Public Sex, Soul Sex, happy endings, hinted Papyrus/Papyrus, that sounds kind of intense but it's pretty fluffy
Language: English
Status: Completed
Published: 2017-03-02
Updated: 2017-03-02
Packaged: 2018-09-27 23:11:29
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,487
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10056125
Author URL: https://archiveofourown.org/users/tealmoon/pseuds/tealmoon
Summary: Everytime he thinks his lover has exhausted every kinky thing they could possibly try, he comes up with something new.





	

The thing was, Blue had to be the sweetest, most innocent-looking skeleton Red had ever seen (though his sample size was, though doubled, still pretty pathetic). Despite being an inch taller than Red, he had a constant air of ‘look how cute and small I am’. He had the same skull structure as Red, but somehow his eye sockets were bigger, his smile wider, almost all of his teeth perfectly flat and white. He still had sharpened canines, but they seemed quaint, like he’d never bit a person in his life. (Red knew from experience how very false that was.)

So, when Blue asked for Red’s soul, hearts in his sockets, hands wringing together in adorable nervousness, Red said yes. He should have known better, but every time Blue came up to him looking that cute, it was easy to forget how devious he was inside. And the results were usually really hot.

It was mid-morning, early enough that he was still pleasantly drowsy, but coherent enough to hold a conversation. Blue was already dressed, ready to take on the day. But this time, he wanted to do it with Red’s soul beside his own, hidden in his rib cage.

They had done normal soul stuff together; a little oral, a little grinding. Red had never had his soul separated from himself, since that would be an obvious death sentence back home. But here, apparently it was an uncommon but safe sex act; your lover could remove your soul and walk off with it. Technically, the soul that appeared during battles and sex was only half of it, and there was another part embedded in a monster, too deep to remove. The ‘soul’ he was passing over was more like a projection of what was inside him.

He didn’t expect it would be too weird, so he offered it over. Probably Blue would duck behind a tree to finger it a little, maybe give it a lick. He’d be out and about (a few shifts around the Underground and some valuable break-time), which might make things a little awkward, but Blue liked that almost-exhibitionist public shit. This probably wouldn’t be as excruciating and thrilling as the time he took Red out for dinner at Napstabot’s nightclub, where the music was loud enough to muffle the tiny hum of the vibrators taped around Red’s pelvis, controlled by a little remote never too far from Blue’s hand.

Blue hiked his shirt up, where his own soul was pulsing in excitement. He guided Red’s soul up into his rib cage, settling it beside its counterpart. It immediately sent a burst of safety and joy through him, and he nearly dropped back onto the mattress, his bones going loose and relaxed. Once his shirt was back in place, Blue lunged forward, hugging him in excitement and dropping toothy kisses against Red’s skull.

“Remember! I’ll have my phone on me, so if you feel uncomfortable at all, just text me! I’ll stop immediately, of course.” He looked so worried, though there wasn’t any need. Sometimes regular sex could set him off, old injuries making touches to his ribs agonizing instead of pleasurable, but soul stuff was almost always good. And if anything too horrible happened, Blue would be able to pick up on his distress just by holding his soul.

He soon hopped back downstairs to make breakfast, while Red dressed himself. Sharing souls with Blue always made him feel energetic—not to the level of his brother or Blue, obviously, but enough that pulling his shorts on didn’t feel like an ordeal. He could feel wisps of Blue, emotions and fragments of thoughts drifting into his mind. It was the best feedback loop; he was picking up on Blue’s happiness, and with every moment that Red’s mood improved, Blue became more and more ecstatic, and it just kept going.

Blue and Boss were making pancakes when he came down, and he grinned, watching them argue about proper cooking technique. Soon Red was presented with a towering stack of pancakes, though most of them were underdone (Blue’s) or slightly burnt (Boss’s). Either way, they tasted fine when drowned in syrup.

Soon Stretch wandered downstairs, and it didn’t escape Red’s notice that all of his pancakes were made by Boss alone, while Blue started on the dishes. Boss had it bad for Stretch—he got screechy and high-pitched whenever Stretch got too close or punny, doling out his most inspired insults and flushing like a Tsunderplane. (The planes in this universe were a lot more mellow than the Yanderplanes they were used to. He’d be worried about his friend otherwise.)

From drunken late nights out together, he gathered that Stretch was picking up on it and maybe even reciprocating a little bit, but it was agonizingly slow. All ‘your bro is acting weird around me, what’s with that? his reactions are hilarious’. He liked Stretch, he really did, the guy was on-par with Red’s Alphys for being his best friend, but he was the densest motherfucker Red had ever met. If not for the betting pool in Snowdin (he put 50G on them hooking up two months from now), he would have barricaded them in a closet and let the sexual tension do its work.

Soon, all of them had to get moving, Stretch and Blue heading into Snowdin forest and Boss and Red taking the boat to Hotland. They split off so Boss could take one of the elevators leading to the Capital, while Red went to his station. When their universe had smashed into this one, Boss had clamored to join the Guard here, ready to follow the same path he took back home. Until the Alphys here, Captain Alphys, took one look at his fighting style and turned him down. Same with Undyne, which had been a rather brutal fight—he half expected Alphys to kill her, not just to beat her down and declare that she couldn’t join the Guard but they could damn well be friends. The ruthless, dusty ‘leave no survivors’ shit didn’t fly in this universe, as a lot of the foreign monsters were learning. There were still brawls occasionally, but this new Underground was like a miracle for most of them, and they weren’t going to give it up.

It had taken a few months of needling and arguments, but he had gotten Boss to set his armor aside, at least for a little while. It helped that Queen Toriel (and wasn’t _that_ a surprise) had decreed that the newcomer monsters could attend the Underground’s college at a reduced tuition, so that they could build their new lives more easily. Between the three of them working, they could easily afford for Boss to go to school and eventually managed to convince him to enroll. Boss and Undyne were still doing the basic, ‘everyone needs these’ classes, but Red was letting himself be hopeful for once. His brother didn’t need to fight anymore.

Now that there were more monsters overall, there were more sentry points set up, in all regions. Red managed to talk his way into getting a few of them for himself, despite being an alternate. (Most of the new available work was construction, building houses for the alternate monsters, but that was way too physical for him, a lot more effort than sentry watch.) It wasn’t so much to watch out for humans, but for the new monsters, who were still getting used to things. This Underground seemed like it had been shifted a few degrees to one side, so it was surprisingly easy for them to get lost. And, if necessary, the sentries kept an eye out for fights, contacting the Guard if they couldn’t break it up themselves.

In the morning, it was Hotland, and Waterfall in the afternoon, a pleasant way to recover from the relentless heat. Wasn’t as scalding as back home, but still could be a headache. Either way, it was money, and he barely had any fights to break up. At most, it was 90% uninterrupted dozing, 10% giving directions. He could definitely handle whatever Blue planned with his soul, without _breaking a sweat_.

Honestly, for the first hour or so, he barely felt a thing. Blue was dedicated to his puzzles, there was no way he’d start fucking Red until they were all inspected and recalibrated. Just the feeling of Blue’s soul beside his was nice enough. He busted out a magazine, settled in, and waited.

It took about an hour and a half, though he didn’t mind; the anticipation was nice. If he concentrated, he could get brief mental flashes from Blue’s vision; mostly trees and snow. Red shuddered pleasantly, feeling a phantom bite of cold that could have only been Blue finally pulling his soul out and holding it in the icy Snowdin air. It became even more intense as he could feel Blue’s tongue against his core, hesitant at first, lapping at it in tiny licks. He could feel it starting to seep red droplets that Blue was diligent in cleaning away.

He pulled up his hood, shivering despite the heat pressing on him, and got a weird look from a passing Vulkin. Luckily she didn’t stop to talk. Maybe someone had walked by on his end or maybe Blue just wanted his hands free, but Red could feel the tiniest scrape of teeth as his soul was enveloped in Blue’s mouth.

It only took a few more minutes of gentle bites and licking. Red was well practiced in having silent orgasms (a holdover from living with a brother who’d take a whimper or moan as a sign of a nightmare that he definitely needed to save Sans from), so he came with barely a sigh, muffled against the counter of his station.

Not a bad sexperiment, overall. The sensory aspect of Blue soul-fucking him in the snow was a _cool_ touch, though the distance was kind of depressing—now that it was over, he wouldn’t mind a cuddle or even just looking Blue in the face. It’d have to wait. He considered texting Blue so they could have a quickie over his lunch break, which was in just a few minutes, but gave up on the notion. He probably needed to save his energy for tonight.

(Because they were having a movie marathon, of course. Had to stay sharp for that.)

Instead, he took a shortcut directly into Muffet’s. Now that his Grillby had moved into Snowdin, setting up his bar on the other side of town, Red split his time between them. Grillby was cooling down just the tiniest bit, but he still got put-out if Red didn’t stop by a few times a week, the needy asshole. Today was a Muffet day, but it was better not to let Grillby even see him coming in or out of the cafe. She smirked as he headed to the front, always finding the one-sided competition hilarious. She had started carrying more condiments too, now that he was a regular.

It only took a few minutes before she passed him a bottle of mustard and a cheese danish, grimacing and turning away as he started to squirt mustard onto the pastry. He had just taken a bite when he felt fingers on his soul.

Ungloved fingers, which was a nice bonus. Blue probably guessed he was on lunch break and wanted a second round with a little more exhibitionism. He’d have to take smaller bites, so he didn’t choke or anything. What a way to go, choking to death on your lunch because you were being long-distance fingerfucked. (Not that skeletons had throats in the traditional sense, but the threat remained.) He made sure not to move or react to how Blue’s fingers were prodding at his essence.

It would have been easier to avoid notice if he had chosen a side booth rather than a seat at the front, but the challenge would be hot in its own way. He didn’t let himself shiver, taking a sip of mustard as he felt a finger pressing against the surface of his soul. Souls weren’t completely solid; they had a texture like really old jello that had hardened on the top. If you pushed enough, you could penetrate through that top layer and get inside. It wasn’t a common sex act in his old universe, and both of them had worried it would disrupt his pitiful HP. No one had ever died doing it, but what if he was the first?

It had taken a lot of research and tentative experimenting before either of them felt comfortable trying it, but these days, Red could take soul penetration pretty well. Blue wasn’t pulling any punches either, pushing in all the way to his carpal bones and slowly dragging his finger in and out. Blue had tiny fingers, but Red’s soul was pretty small itself. Soon he was adding a second finger, wiggling them around in Red’s core with unmistakable, mischievous glee.

Shit, was he starting to sweat? He could keep himself decently quiet and still, after all his practice with Blue’s ‘you don’t get to orgasm if you move or react’ games. Those weren’t his favorites, but Blue really liked the challenge of trying to make him fall apart. The sweating, on the other hand, he couldn’t help that. And Blue was really starting to going at it, thrusting when he usually took it slow, fingers nearly pushing out the other side with their force. If he concentrated really hard, he could almost hear how it sounded, slick and wet...

Red jammed the rest of his danish between his teeth a moment before climax took him again, biting down to keep himself silent, legs trembling.

And Blue didn’t stop. His movements slowed down but didn’t withdraw, waving his fingers around in the depths of Red’s soul. And was that a third finger...?

He needed to get out of here. He still had a good ten minutes left in his break, but if Blue kept this up, he was going to lose control and start moaning in the middle of the cafe, lunch crowd be damned. He tossed down a few coins, who knew if it was the right amount but it was better than the drawn-out teasing and bantering about his tab. Muffet gave him a strange look, but he just shrugged and grinned, carefully hopping off the barstool though his legs threatened to collapse.

He barely reached the doorway before he was tumbling into a shortcut, luckily managing to appear beside his Waterfall station, rather than halfway across the Underground. He wobbled over to the chair, falling onto it.

His cellphone buzzed, the fingers inside his soul going still. Blue had texted him. _‘Are you okay with going further? I want to try something! :D’_ What did that mean? Blue could get creative, so ‘further’ covered a lot of territory.

_‘go ahead’_ Maybe he was sealing his fate with that, but he wanted to know. At least now he could be sure that Blue had his phone out and would immediately notice if Red safeworded through text.

Blue started to move again a few seconds later, fingers spreading through the mass of his soul. He had to wonder how much of a mess that had to be creating; if Blue wasn’t careful, he’d have crimson stains down his front. And even if he managed to keep himself clean, that would still be a fuckload of red fluid left on the snow... He clutched at the counter, phalanges creaking.

Four fingers. Blue was slowing down, stroking rather than thrusting. His core felt so full that it barely made a difference. His joints were starting to glow a gentle red, visible through his clothing, which felt heavy and strange against his increasingly sensitive bones. He laid his head down on the counter, gasping a little as Blue eased out partway to add in his thumb. Blue was barely moving now, his fingertips gently drifting in circular motions. He briefly considered touching himself, maybe to grab his spine or his coccyx, but it felt like any more stimulation would make him fall apart.

He wasn’t used to it being this intense, not without Blue beside him. This part of Waterfall didn’t get much traffic, but he found himself slipping off his seat anyway, tucking himself under the counter of his station. He didn’t want anyone but Blue to see him like this: glowing, breathing heavily, coming undone. Hopefully people would assume he was still on break.

Tears were starting to bead up in his eye sockets, and a few times his hand twitched towards his phone, wondering if he needed to stop. It felt so amazing, but at the same time, his soul seemed at its limit. If he climaxed, would it burst? Would it fall apart around Blue’s hand, unable to keep its shape?

Fuck, that would be such a great way to die.

It felt like his orgasm was moving as slow as Blue, to the point that he could practically see it on the horizon, with plenty of time to stuff his sleeve into his mouth, ready to muffle himself. Red wasn’t a screamer usually, but for something like this, he could probably make an exception.

He felt his skull fall backward, hitting the wood with a gentle thump, but there wasn’t any room left in him for pain, just endless pleasure sweeping through him, wiping his mind clean. It seemed to last forever.

As the shuddering tapered off, Blue began to slip his fingers out, gently withdrawing to keep from hurting him. Red wanted him to stay, wanted that feeling forever, but it was probably for the best. After what seemed like minutes, Blue’s hand finally pulled out of him, provoking one last moan. His limbs weren’t quite working properly, and he dropped his phone a few times, but he got a good grip on it. And then, of course, starting mistyping. It seemed Blue was waiting patiently, though.

_‘end-scene come get me <3’_

Though his hands were shaking, he managed to get those few words out, hoping it was reassuring enough. He didn’t want Blue to worry about him during the time it’d take him to get from Snowdin to Waterfall. He needed to see his lover, not just feel him from a distance, and his shift was closer to done than he had expected. Had Blue really been fucking him for that long?

It seemed like Blue had run the whole way regardless, panting and covered in sweat, muttering something in confusion before he leaned over the counter and saw Red. “There you are!” He crawled in after him, and luckily there was just about enough room for two small skeletons. “How are you feeling? I know that was pretty intense for something done remotely. Any pain?” Blue dug around in his rib cage, producing Red’s soul. It was brighter and damper than usual, but the hole Blue had created already sealed itself up, as if nothing had happened despite the aftershocks still working their way through him.

He didn’t want to take it back, wanting his hands on him forever, but Red let Blue ease up his shirt, putting his soul back where it belonged. He sighed, as Blue’s arms wrapped around him. “Doesn’t hurt. It was...” Amazing? Intense? So powerful the force of it should have broken the barrier? “...really hot. But maybe we could do it in the same room next time?”

“Of course!” Blue nuzzled at his shoulder. “It’s really amazing to see, I should have taken a photo to text you, but, you know. I _was_ a bit occupied at the time. Had my hands full, you could say.”

He groaned, leaning into Blue; it was getting harder to hold himself up. “Don’t start making puns or I’m gonna nut again.”

Blue cackled. “That’s gross, don’t be so silly! _Come_ on, don’t you want to go home? And you’re pretty sweaty, we should take a bath together or something.” He let go and squirmed out from under the counter, standing and offering Red his hand. “Bit cramped under there, isn’t it?”

“Yeah, but I dunno if I can get up.” His entire body felt like one big wobble as Blue heaved him up, gravity magic dragging Red into a passable vertical position. His soul was so sensitive that using magic on it forced a pleasured whine out of him, loud enough that the Echo Flower on the other side of the room picked it up. It managed to repeat it a few times before Blue hurried over, coughing theatrically to replace the sound. _That_ would have been an interesting surprise to leave for the next sentry.

Wrapping his arm around Red’s shoulder, his magic still compensating for most of his lover’s weight, Blue led him home.

**Author's Note:**

> “Wow, I’ve been stressed and not very confident about my writing, I should write something easy and cute, like....fisting.” With a side of Underfell glitching into Underswap, saving all of the fellmonsters from their ‘kill or be killed’ world, not just the skeletons. 
> 
> Also, kind of annoying that no one has made up nicknames for different versions of Alphys and Undyne, makes it hard to distinguish them. Can we get on that?


End file.
